1. Field of the Invention
The present invention relates generally to a tree pruner, and more particularly to a positioning or locating structure of an expandable rod of the tree pruner.
2. Description of Related Art
The tree pruner is generally provided with an expandable rod to facilitate the removing of dead or living parts of a tall plant.
As shown in FIGS. 1-4, an expandable rod of the prior art is formed of an inner tube 50 and an outer tube 60. The inner tube 50 is slidably fitted into the outer tube 60, thereby enabling the expandable rod of the prior art to be adjusted in length. The inner tube 50 is provided at one end with a drive block 51, which is located by a stop block 52. The stop block 52 is provided with a through slot 53, an Inner slot 54 opposite in location to the through slot 53, and two eccentric arcuate recesses 55. The eccentric arcuate recesses 55 are provided with a stop projection 56. The stop block 52 is provided in the outer wall with two reverse ratchet portions 57. The stop block 52 is rotatably joined with the drive block 51 of the inner tube 50. In light of the contact surface between the drive block 51 and the eccentric arcuate recess 55 of the stop block 52 being smooth, the drive block 51 is apt to slide at the time when the outer tube 60 is twisted slightly. As a result, the inner tube 50 and the outer tube 60 can not be securely located. The work efficiency of the tree pruner is thus adversely affected. In addition, the stop projections 56 are vulnerable to damage which is caused by the impact of the drive block 51, as illustrated in FIG. 3.
The primary objective of the present invention is to provide a structure for locating securely an expandable rod of the tree pruner.
The locating structure of the present invention comprises an outer tube, an inner tube provided at one end with a drive block, and a stop block which is fitted over the drive block such that the stop block serves to locate securely the outer tube and the inner tube.